JP6756336B2 - Power storage element and manufacturing method of power storage element - Google Patents

Description

The present invention relates to a power storage element including an electrode body and a current collector, and a method for manufacturing the same.

A power storage element having an electrode body and a current collector and having a structure in which the electrode body and the current collector are joined is widely known. Then, conventionally, in order to firmly bond the electrode body and the current collector, a configuration in which the current collector is immersed in the electrode body has been proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-273178

However, when the current collector is immersed in the electrode body to firmly join the electrode body and the current collector as in the conventional power storage element, the performance of the power storage element may deteriorate. There is.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a power storage element capable of suppressing deterioration of the performance of the power storage element while firmly joining the electrode body and the current collector. And.

In order to achieve the above object, the power storage element according to one aspect of the present invention is a power storage element including an electrode body and a current collector, and the current collector is an electrode connection portion connected to the electrode body. The electrode connecting portion has a first portion and a second portion which is thinner than the first portion and is joined to the electrode body, and has the second portion and the electrode connecting portion. One of the electrode bodies has a first convex portion that protrudes toward the other at the joint portion.

According to the power storage element of the present invention, it is possible to suppress deterioration of the performance of the power storage element while firmly joining the electrode body and the current collector.

FIG. 1 is a perspective view schematically showing the appearance of the power storage element according to the embodiment of the present invention. FIG. 2 is a perspective view showing components arranged inside the container of the power storage element according to the embodiment of the present invention. FIG. 3 is an exploded perspective view showing each component when the power storage element according to the embodiment of the present invention is disassembled. FIG. 4 is a perspective view showing a configuration of a positive electrode current collector according to an embodiment of the present invention. FIG. 5 is a cross-sectional view showing a configuration in which the positive electrode current collector according to the embodiment of the present invention is joined to the positive electrode focusing portion of the electrode body. FIG. 6 is a cross-sectional view showing a configuration of a joint portion between the positive electrode current collector and the electrode body according to the embodiment of the present invention. FIG. 7A is a flowchart showing a method of manufacturing a power storage element according to an embodiment of the present invention. FIG. 7B is a flowchart showing a method of manufacturing a power storage element according to an embodiment of the present invention. FIG. 8 is a cross-sectional view showing a configuration in which the positive electrode current collector according to the first modification of the embodiment of the present invention is joined to the positive electrode focusing portion of the electrode body. FIG. 9 is a cross-sectional view showing a configuration in which the positive electrode current collector according to the second modification of the embodiment of the present invention is joined to the positive electrode focusing portion of the electrode body. FIG. 10 is a cross-sectional view showing a configuration in which the positive electrode current collector according to the third modification of the embodiment of the present invention is joined to the positive electrode focusing portion of the electrode body. FIG. 11 is a perspective view showing the configuration of the positive electrode current collector according to the fourth modification of the embodiment of the present invention. FIG. 12 is a cross-sectional view showing a configuration of a joint portion between the positive electrode current collector and the electrode body according to the fifth modification of the embodiment of the present invention.

When the current collector is immersed in the electrode body to firmly join the electrode body and the current collector as in the conventional power storage element, there is a problem that the performance of the power storage element may deteriorate. ..

That is, in the above-mentioned conventional power storage element, when joining the electrode body and the current collector, a large force is required to immerse the current collector in the electrode body, so that it is necessary to use a large joining device. The electrode body is bonded to the current collector at the portion where the active material is not coated (active material uncoated portion), but when a large joining device is placed in the active material uncoated portion, the electrode body is said to be applicable. It may be necessary to widen the uncoated part of the active material. Since the uncoated portion of the active material is a portion of the electrode body that does not contribute to power generation, when the uncoated portion of the active material is widened, the energy density of the power storage element is lowered and the performance of the power storage element is lowered. ..

The present invention has been made in view of the above problems, and an object of the present invention is to provide a power storage element capable of suppressing deterioration of the performance of the power storage element while firmly joining the electrode body and the current collector. And.

In order to achieve the above object, the power storage element according to one aspect of the present invention is a power storage element including an electrode body and a current collector, and the current collector is an electrode connection portion connected to the electrode body. The electrode connecting portion has a first portion and a second portion which is thinner than the first portion and is joined to the electrode body, and has the second portion and the electrode connecting portion. One of the electrode bodies has a first convex portion that protrudes toward the other at the joint portion.

According to this, in the power storage element, either one of the second portion of the current collector and the electrode body has a first convex portion protruding toward the other at the joint portion. That is, either one of the second part of the current collector and the electrode body forms the first convex portion and bites into the other, so that the current collector and the electrode body are firmly joined. Here, since the second portion is a portion thinner than the first portion, the first convex portion can be formed with a small force to join the current collector and the electrode body. Therefore, since a small joining device can be used, the uncoated portion of the active material of the electrode body is reduced (the width of the uncoated portion of the active material is narrowed), and the decrease in the energy density of the power storage element is suppressed. be able to. As described above, according to the power storage element, it is possible to suppress deterioration of the performance of the power storage element while forming the first convex portion and firmly joining the electrode body and the current collector. Further, since the first part of the current collector is thicker than the second part, the performance of the power storage element is deteriorated by suppressing the decrease in the strength of the current collector in the second part by the first part. Can be suppressed.

Further, the current collector further has a terminal connection portion connected to the electrode terminal, and at least a part of the first portion is arranged between the terminal connection portion and the second portion. You may decide.

According to this, in the current collector, at least a part of the first part is arranged between the terminal connection part connected to the electrode terminal and the second part joined to the electrode body. That is, since a thick portion is arranged between the terminal connection portion and the second portion, the strength between the terminal connection portion and the second portion can be secured, and the performance of the power storage element deteriorates. Can be suppressed.

Further, the electrode connecting portion may have a plurality of the second portions, and at least a part of the first portion may be arranged between the plurality of second portions.

According to this, in the current collector, at least a part of the first part is arranged between the plurality of second parts. That is, since the thick portion is arranged between the thin second portions, it is possible to secure the strength between the plurality of second portions and suppress the deterioration of the performance of the power storage element. it can.

Further, at least a part of the first part may be arranged around the second part.

According to this, in the current collector, at least a part of the first part is arranged around the second part. That is, since the thick portion is arranged around the thin second portion, the strength around the second portion can be ensured, and the deterioration of the performance of the power storage element can be suppressed.

Further, a cover member is provided at a position sandwiching the electrode body with the electrode connecting portion, and the cover member includes a first cover portion and a second cover portion having a thickness thinner than that of the first cover portion. However, it may have a second cover portion to be joined to the electrode body.

According to this, even in the cover member, since the second cover portion having a thin thickness is bonded to the electrode body, the current collector and the cover member can be bonded to the electrode body with a smaller force. Therefore, since a smaller joining device can be used, it is possible to further suppress deterioration in the performance of the power storage element.

Further, in order to achieve the above object, the method for manufacturing a power storage element according to one aspect of the present invention is to manufacture a power storage element including an electrode body and a current collector having an electrode connecting portion connected to the electrode body. In the method, a thin-walled portion having a thickness thinner than other portions is formed in the electrode connecting portion, and the thin-walled portion and the electrode body are joined by plastic deformation.

According to this, in the method of manufacturing a power storage element, a thin-walled portion having a thickness thinner than other portions is formed at the electrode connecting portion of the current collector, and the thin-walled portion and the electrode body are joined by plastically deforming. .. That is, by joining the current collector and the electrode body in the thin-walled portion, the current collector and the electrode body can be plastically deformed and joined with a small force. Therefore, since a small joining device can be used, the number of uncoated parts of the active material of the electrode body can be reduced (the width of the uncoated parts of the active material is narrowed), and the deterioration of the performance of the power storage element can be suppressed. Can be done. Further, since the portion other than the thin-walled portion of the current collector is thick, the performance of the power storage element is deteriorated by suppressing the decrease in the strength of the current collector in the thin-walled portion by the other portion. Can be suppressed.

Hereinafter, the power storage element according to the embodiment of the present invention will be described with reference to the drawings. In addition, all of the embodiments described below show a preferable specific example of the present invention. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, manufacturing processes, order of manufacturing processes, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Further, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept are described as arbitrary components. Moreover, in each figure, the dimensions and the like are not exactly illustrated.

(Embodiment)
First, the configuration of the power storage element 10 will be described.

FIG. 1 is a perspective view schematically showing the appearance of the power storage element 10 according to the embodiment of the present invention. Further, FIG. 2 is a perspective view showing components arranged inside the container 100 of the power storage element 10 according to the embodiment of the present invention. Specifically, FIG. 2 is a perspective view showing a configuration in which the container body 111 is separated from the power storage element 10. That is, the figure shows a state after the positive electrode current collector 500 and the negative electrode current collector 600 are joined to the electrode body 400.

Further, FIG. 3 is an exploded perspective view showing each component when the power storage element 10 according to the embodiment of the present invention is disassembled. That is, the figure shows a state before joining the positive electrode current collector 500 and the negative electrode current collector 600 to the electrode body 400. Further, in the figure, the container body 111 is omitted.

In these figures, the Z-axis direction is shown as the vertical direction, and the Z-axis direction will be described below as the vertical direction. However, depending on the usage mode, the Z-axis direction may not be the vertical direction. The axial direction is not limited to the vertical direction. The same applies to the following figures.

The power storage element 10 is a secondary battery capable of charging electricity and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. For example, the power storage element 10 is applied to a power source for automobiles such as an electric vehicle (EV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV), a power source for electronic devices, a power source for power storage, and the like. ..

The power storage element 10 is not limited to the non-aqueous electrolyte secondary battery, and may be a secondary battery other than the non-aqueous electrolyte secondary battery, a capacitor, and further charged by the user. It does not matter if it is a primary battery that can use the stored electricity without using the battery. Further, in the present embodiment, the rectangular (square) power storage element 10 is illustrated, but the shape of the power storage element 10 is not limited to the rectangular shape, and may be a cylindrical shape, a long cylindrical shape, or the like. Alternatively, it may be a laminated type power storage element.

As shown in FIG. 1, the power storage element 10 includes a container 100, a positive electrode terminal 200, and a negative electrode terminal 300. Further, as shown in FIG. 2, the electrode body 400, the positive electrode current collector 500, and the negative electrode current collector 600 are housed inside the container 100.

In addition to the above components, spacers arranged on the sides of the positive electrode current collector 500 and the negative electrode current collector 600, and a gas discharge valve for releasing the pressure in the container 100 when the pressure rises. Alternatively, an insulating film or the like that wraps the electrode body 400 or the like may be arranged. Further, although a liquid such as an electrolytic solution (non-aqueous electrolyte) is sealed inside the container 100, the illustration of the liquid is omitted. The type of the electrolytic solution is not particularly limited as long as it does not impair the performance of the power storage element 10, and various types can be selected.

The container 100 is composed of a container main body 111 having a rectangular tubular shape and a bottom, and a lid 110 which is a plate-shaped member that closes the opening of the container main body 111. Further, the container 100 can be sealed inside by accommodating the electrode body 400 or the like inside and then welding the lid body 110 and the container body 111 or the like. The materials of the lid 110 and the container body 111 are not particularly limited, and can be weldable metals such as stainless steel, aluminum, and aluminum alloy, but resins can also be used.

The electrode body 400 includes a positive electrode, a negative electrode, and a separator, and is a power storage element capable of storing electricity. The positive electrode is a positive electrode active material layer formed on a positive electrode base material layer which is a long strip-shaped current collecting foil made of aluminum, an aluminum alloy, or the like. The negative electrode is a negative electrode active material layer formed on a negative electrode base material layer which is a long strip-shaped current collecting foil made of copper, a copper alloy, or the like. As the separator, for example, a microporous sheet made of resin or a non-woven fabric can be used. As the current collector foil, known materials such as nickel, iron, stainless steel, titanium, calcined carbon, conductive polymer, conductive glass, and Al—Cd alloy can also be used as appropriate.

The electrode body 400 is formed by winding what is arranged in layers so that the separator is sandwiched between the positive electrode and the negative electrode. Specifically, in the electrode body 400, the positive electrode and the negative electrode are wound so as to be displaced from each other in the direction of the winding axis (virtual axis parallel to the X-axis direction in the present embodiment) via the separator. .. Then, in the positive electrode and the negative electrode, the active material is not coated (the active material layer is not formed) and the base material layer is exposed at the edge portions in the shifted directions (active material uncoated portion). have.

That is, the electrode body 400 has a positive electrode focusing portion 410 in which the active material uncoated portion of the positive electrode is laminated and bundled at one end portion in the winding axis direction (the end portion on the plus side in the X axis direction). .. Further, the electrode body 400 has a negative electrode focusing portion 420 in which the active material uncoated portion of the negative electrode is laminated and bundled at the other end portion in the winding axis direction (the end portion on the minus side in the X axis direction). There is. For example, the thickness of the active material uncoated portion (current collector foil) of the positive electrode and the negative electrode is about 5 μm to 20 μm, and when these are bundled, for example, about 30 to 40 sheets, the positive electrode focusing portion 410 and the negative electrode focusing portion 420 Is formed.

Here, as the positive electrode active material used for the positive electrode active material layer, any known material can be appropriately used as long as it is a positive electrode active material that can occlude and release lithium ions. For example, a composite oxide represented by Li _x MO _y (M represents at least one transition metal) (Li _x CoO ₂ , Li _x NiO ₂ , Li _x Mn ₂ O ₄ , Li _x MnO ₃ , Li _x Ni). _y Co _(1-y) O ₂ , Li _x N _y Mn _z Co _(1-y-z) O ₂ , Li _x N _y Mn _(2-y) O ₄ etc.), or Li _w Me _x (XO) _y ) _z (Me represents at least one transition metal, X is, for example, P, Si, B, V) polyanionic compounds (LiFePO ₄ , LiMnPO ₄ , LiNiPO ₄ , LiCoPO ₄ , Li ₃ V ₂ (PO) ₄ ) ₃ , Li ₂ MnSiO ₄ , Li ₂ CoPO ₄ F, etc.) can be selected. In addition, the elements or polyanions in these compounds may be partially substituted with other elements or anion species. Further, examples thereof include, but are not limited to, conductive polymer compounds such as disulfide, polypyrrole, polyaniline, polyparastyrene, polyacetylene, and polyacene-based materials, and pseudo-graphite structural carbonaceous materials. These may be used alone or in any combination and ratio of two or more.

Further, as the negative electrode active material used for the negative electrode active material layer, a known material can be appropriately used as long as it is a negative electrode active material capable of occluding and releasing lithium ions. For example, in addition to lithium metals and lithium alloys (lithium metal-containing alloys such as lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloys), lithium can be stored and released. Alloys, carbon materials (eg graphite, non-graphitizable carbon, easily graphitized carbon, low temperature fired carbon, amorphous carbon, etc.), metal oxides, lithium metal oxides (Li ₄ Ti ₅ O _12, etc.), polyphosphate compounds And so on. These may be used alone or in any combination and ratio of two or more.

In the present embodiment, the cross-sectional shape of the electrode body 400 is shown as an oval shape, but it may be circular or elliptical. Further, the shape of the electrode body 400 is not limited to the winding type, and may be a shape in which flat plate-shaped electrode plates are laminated, a shape in which the electrode plates are folded in a bellows shape, or the like.

The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 400, and the negative electrode terminal 300 is an electrode terminal electrically connected to the negative electrode of the electrode body 400. That is, the positive electrode terminal 200 and the negative electrode terminal 300 lead the electricity stored in the electrode body 400 to the external space of the power storage element 10, and the electricity is stored in the internal space of the power storage element 10 in order to store electricity in the electrode body 400. It is a metal electrode terminal for introducing.

Further, the positive electrode terminal 200 and the negative electrode terminal 300 are attached to a lid 110 arranged above the electrode body 400. Specifically, as shown in FIG. 3, the positive electrode terminal 200 has a positive electrode when the protruding portion 210 is inserted into the through hole 110a of the lid 110 and the opening 511 of the positive electrode current collector 500 and crimped. It is fixed to the lid 110 together with the current collector 500. Similarly, in the negative electrode terminal 300, the protruding portion 310 is inserted into the through hole 110b of the lid 110 and the opening 611 of the negative electrode current collector 600 and crimped, so that the lid 110 is together with the negative electrode current collector 600. Is fixed to.

A gasket or the like is arranged between the lid body 110 and the positive electrode terminal 200 and between the lid body 110 and the positive electrode current collector 500 in order to improve the insulating property and the airtightness. The figure is omitted. The same applies to the negative electrode side.

The positive electrode current collector 500 is arranged between the positive electrode focusing portion 410 of the electrode body 400 and the side wall of the container body 111, and has conductivity and rigidity that are electrically connected to the positive electrode terminal 200 and the positive electrode of the electrode body 400. It is a member provided with. Further, the negative electrode current collector 600 is arranged between the negative electrode focusing portion 420 of the electrode body 400 and the side wall of the container body 111, and is electrically connected to the negative electrode terminal 300 and the negative electrode of the electrode body 400. It is a member having rigidity.

Specifically, the positive electrode current collector 500 and the negative electrode current collector 600 have a conductive plate shape that is arranged in a bent state along the side wall and the lid 110 from the side wall of the container body 111 to the lid 110. It is a member. The positive electrode current collector 500 and the negative electrode current collector 600 are fixedly connected (joined) to the lid 110. Further, the positive electrode current collector 500 and the negative electrode current collector 600 are fixedly connected (bonded) to the positive electrode focusing portion 410 and the negative electrode focusing portion 420 of the electrode body 400, respectively. With this configuration, the electrode body 400 is held (supported) in a state of being suspended from the lid 110 by the positive electrode current collector 500 and the negative electrode current collector 600, and shaking due to vibration, impact, or the like is suppressed.

The material of the positive electrode current collector 500 is not limited, but for example, it is made of aluminum or an aluminum alloy like the positive electrode base material layer of the electrode body 400. Further, the material of the negative electrode current collector 600 is not limited, but is formed of, for example, copper or a copper alloy like the negative electrode base material layer of the electrode body 400.

Here, as shown in FIG. 2, the positive electrode current collector 500 is joined to the positive electrode focusing portion 410 of the electrode body 400 at a plurality of joining portions 20. Further, the negative electrode current collector 600 is joined to the negative electrode focusing portion 420 of the electrode body 400 at a plurality of joining portions 30. The specific configurations of the positive electrode current collector 500 and the negative electrode current collector 600, and the specific configurations of the joint portions 20 and 30 will be described in more detail below. Since the positive electrode current collector 500 and the negative electrode current collector 600 have the same configuration, the configurations of the positive electrode current collector 500 and the junction 20 will be described below, and the negative electrode current collector 600 and the negative electrode current collector 600 The description of the configuration of the joint portion 30 will be omitted.

First, the configuration of the positive electrode current collector 500 will be described. FIG. 4 is a perspective view showing the configuration of the positive electrode current collector 500 according to the embodiment of the present invention. Note that the figure shows the configuration of the positive electrode current collector 500 in a state before being joined to the electrode body 400. Further, FIG. 5 is a cross-sectional view showing a configuration in which the positive electrode current collector 500 according to the embodiment of the present invention is joined to the positive electrode focusing portion 410 of the electrode body 400. Specifically, the figure shows a configuration in which the positive electrode current collector 500 and the positive electrode focusing portion 410 shown in FIG. 2 are cut in a YZ plane passing through the joint portion 20.

As shown in these figures, the positive electrode current collector 500 includes the terminal connecting portion 510 and the electrode connecting portions 520 and 530 extending from both ends of the terminal connecting portion 510 in the Y-axis direction toward the negative side in the Z-axis direction. And have.

The terminal connection portion 510 is a portion connected to the positive electrode terminal 200. That is, the terminal connection portion 510 is a flat plate-shaped portion arranged on the positive electrode terminal 200 side (upper side, positive side in the Z-axis direction) of the positive electrode current collector 500, and is electrically and mechanically (physically) connected to the positive electrode terminal 200. ) Is connected.

Specifically, the terminal connection portion 510 is formed with an opening 511 which is a circular through hole into which the protruding portion 210 of the positive electrode terminal 200 is inserted. Then, the terminal connecting portion 510 is fixed to the positive electrode terminal 200 by inserting the protruding portion 210 into the opening 511 and crimping it together with the lid 110. That is, the protruding portion 210 is, for example, a rivet, and the terminal connecting portion 510 is fixed to the lid 110 together with the positive electrode terminal 200 by caulking with the rivet.

The opening 511 is not limited to a circular shape and may be an elliptical shape or a rectangular shape, but it is preferable that the opening portion 511 has a shape corresponding to the outer shape of the protruding portion 210. Further, the opening 511 is not limited to the through hole, and may be a notch cut out in a semicircular shape or a rectangular shape.

The electrode connecting portions 520 and 530 are portions connected to the electrode body 400. That is, the electrode connection portions 520 and 530 are flat plate-shaped portions arranged on the electrode body 400 side (lower side, negative side in the Z-axis direction) of the positive electrode current collector 500, and are electrically and mechanically attached to the electrode body 400. Connected (physically). Specifically, as shown in FIG. 5, the electrode connecting portions 520 and 530 are connected to the flat focusing portions 411 and 421, which are two opposing flat focusing portions of the positive electrode focusing portion 410 of the electrode body 400, respectively. Will be done.

More specifically, the electrode connecting portion 520 is a long and flat portion extending so as to hang down from the end of the terminal connecting portion 510 on the negative side in the Y-axis direction toward the negative side in the Z-axis direction. It is connected to the flat focusing portion 411. Similarly, the electrode connecting portion 530 is a long and flat portion extending so as to hang down from the end of the terminal connecting portion 510 on the positive side in the Y-axis direction toward the negative side in the Z-axis direction. Yes, it is connected to the flat focusing section 412. Here, since the electrode connecting portion 520 and the electrode connecting portion 530 have the same configuration, the configuration of the electrode connecting portion 520 will be described below, and the description of the configuration of the electrode connecting portion 530 will be omitted.

The electrode connecting portion 520 has a first portion 521 and a second portion 522 which is thinner than the first portion 521. That is, the second portion 522 is a thin-walled portion formed in the electrode connecting portion 520. Further, the first part 521 has a terminal side first part 521a, an intermediate first part 521b, and a tip side first part 521c. The second portion 522 has a terminal-side second portion 522a and a tip-side second portion 522b.

The terminal-side first part 521a is a rectangular and flat plate-shaped portion arranged between the terminal connection portion 510 and the terminal-side second portion 522a of the second portion 522. That is, one end (the end on the plus side in the Z-axis direction) of the terminal-side first part 521a is connected to the terminal connection portion 510, and the other end (the end on the minus side in the Z-axis direction) is connected to the terminal-side second part 522a. It is a connected long part extending in the Z-axis direction.

The intermediate first part 521b is a rectangular and flat plate-shaped portion arranged between the terminal side second part 522a and the tip side second part 522b of the second part 522. That is, one end (the end on the plus side in the Z-axis direction) of the intermediate first part 521b is connected to the second part 522a on the terminal side, and the other end (the end on the minus side in the Z-axis direction) is the second part 522b on the tip side. It is a substantially square-shaped part (when viewed from the Y-axis direction) in a plan view connected to.

The tip side first part 521c is a rectangular and flat plate-shaped portion arranged below the tip side second part 522b (minus side in the Z-axis direction). That is, the tip-side first portion 521c is a long portion extending in the Z-axis direction in which one end (the end on the plus side in the Z-axis direction) is connected to the tip-side second portion 522b.

In the present embodiment, the terminal side first part 521a, the intermediate first part 521b, and the tip side first part 521c are formed so as to have the same thickness (thickness in the Y-axis direction). It may be formed so as to have different thicknesses.

The terminal-side second portion 522a is a rectangular and flat plate-shaped portion arranged between the terminal-side first portion 521a and the intermediate first portion 521b of the first portion 521. That is, one end (the end on the plus side in the Z-axis direction) of the second portion 522a on the terminal side is connected to the first part 521a on the terminal side, and the other end (the end on the minus side in the Z-axis direction) is the intermediate first part 521b. It is a substantially square-shaped part (when viewed from the Y-axis direction) in a plan view connected to.

Further, the terminal side second portion 522a is a thin portion formed so as to be thinner than the terminal side first portion 521a and the intermediate first portion 521b by press working, cutting, or the like. For example, the terminal-side second portion 522a is formed to have a thickness of about 1/2 to 2/3 of the terminal-side first portion 521a and the intermediate first portion 521b. When the thickness of the terminal side first part 521a and the intermediate first part 521b are different, the terminal side second part 522a is thicker than either of the terminal side first part 521a and the intermediate first part 521b. It may be formed thin, but it is preferable that the thickness is formed thinner than both the terminal side first part 521a and the intermediate first part 521b.

The tip side second portion 522b is a rectangular and flat plate-shaped portion arranged between the intermediate first part 521b of the first part 521 and the tip side first part 521c. That is, one end (the end on the plus side in the Z-axis direction) is connected to the intermediate first part 521b, and the other end (the end on the minus side in the Z-axis direction) is the tip-side first part 521c. It is a substantially square-shaped part (when viewed from the Y-axis direction) in a plan view connected to.

Further, the tip side second portion 522b is a thin-walled portion formed so as to be thinner than the intermediate first part 521b and the tip side first part 521c by press working, cutting, or the like. For example, the tip side second portion 522b is formed to have a thickness of about 1/2 to 2/3 of the intermediate first part 521b and the tip side first part 521c. When the thickness of the intermediate first part 521b and the tip side first part 521c are different, the tip side second part 522b is thicker than either of the intermediate first part 521b and the tip side first part 521c. It may be formed thin, but it is preferable that the thickness is formed thinner than both the intermediate first part 521b and the tip side first part 521c.

As described above, the electrode connecting portion 520 has a plurality of first portions and a plurality of second portions having a thickness thinner than the plurality of first portions between the plurality of first portions. .. That is, at least a part (terminal side first part 521a) of the first part 521 is arranged between the terminal connection portion 510 and the second part (terminal side second part 522a), and at least a part (terminal side first part 522a) is arranged. The intermediate first part 521b) is arranged between a plurality of second parts (terminal side second part 522a and tip side second part 522b).

Here, as shown in FIG. 5, the second portion 522 is a portion to be joined to the electrode body 400. That is, in the electrode connecting portion 520, the first part 521 is connected (contacted) with the electrode body 400 but is not joined (fixed), and the thin second portion 522 is connected to the electrode body 400. It is joined (fixed). Specifically, the second portion 522 is mechanically joined to the flat focusing portion 411 of the positive electrode focusing portion 410 at two locations, the terminal side second portion 522a and the tip side second portion 522b, and the two joining portions 20 Is formed.

More specifically, the cover member 700 is arranged inside the flat focusing portion 411, and the terminal side second portion 522a and the tip side second portion 522b, the flat focusing portion 411, and the cover member 700 are mechanically arranged. It is joined to form two joints 20. The cover member 700 is a cover that protects the flat focusing portion 411 arranged at a position sandwiching the flat focusing portion 411 of the positive electrode focusing portion 410 of the electrode body 400 with the electrode connecting portion 520. The cover member 700 is a rectangular and flat plate-shaped member extending in the Z-axis direction along the flat focusing portion 411, and is formed so as to have a uniform thickness in the state before joining. Similarly, the cover member 700 is also arranged on the electrode connecting portion 530 side.

The material of the cover member 700 is not particularly limited, but is, for example, a metal member made of aluminum or an aluminum alloy, like the positive electrode base material layer of the electrode body 400. A cover member is also arranged on the negative electrode side, and the material of the cover member on the negative electrode side is not particularly limited. For example, like the negative electrode base material layer of the electrode body 400, copper or a copper alloy or the like is used. It is a metal member formed of.

Next, the configuration of the joint portion 20 will be described. FIG. 6 is a cross-sectional view showing the configuration of the joint portion 20 between the positive electrode current collector 500 and the electrode body 400 according to the embodiment of the present invention. Specifically, the figure is an enlarged view showing the configuration of the joint portion 20 formed by joining the terminal-side second portion 522a, the flat focusing portion 411, and the cover member 700 shown in FIG. It is a sectional view.

As shown in FIG. 6, the second portion 522, the electrode body 400, and the cover member 700 have a first convex portion that protrudes toward the cover member 700 side (plus side in the Y-axis direction in the figure) at the joint portion 20. doing. That is, one of the second portion 522 and the electrode body 400 (in the present embodiment, the second portion 522) protrudes toward the other (in the present embodiment, the electrode body 400) at the joint portion 20. It has a single convex portion (the first current collector convex portion 523a described later). Further, the other (electrode body 400) has a first convex portion (first electrode body convex portion 411a described later) that protrudes toward the opposite side of the one (second part 522) at the joint portion 20. ing. Further, either one of the cover member 700 and the electrode body 400 (in the present embodiment, the electrode body 400) is the first convex protruding toward the other (in the present embodiment, the cover member 700) at the joint portion 20. It has a portion (first electrode body convex portion 411a). Further, the other (cover member 700) has a first convex portion (first cover convex portion 700a described later) that protrudes toward the opposite side of the one (electrode body 400) at the joint portion 20. ..

Further, the first convex portion has a second convex portion that protrudes in a direction intersecting the protruding direction of the first convex portion. The first convex portion and the second convex portion are formed, for example, by plastically deforming the second portion 522, the electrode body 400, and the cover member 700 at the joint portion 20. In the present embodiment, in the joint portion 20, the second portion 522, the electrode body 400 and the cover member 700 are formed by caulking (more specifically, by clinch joining).

Specifically, in the joint portion 20, the terminal-side second portion 522a of the second portion 522 has a first current collector convex portion 523a protruding toward the flat focusing portion 411 of the electrode body 400. That is, the first current collector convex portion 523a is a cylinder protruding in a direction (Y-axis direction plus side) orthogonal to the joint surface (plane parallel to the XZ plane) between the terminal side second portion 522a and the flat focusing portion 411. It is a convex part of the shape. In other words, the first current collector convex portion 523a has a shape recessed from the outer surface of the terminal side second portion 522a (the surface parallel to the XZ plane on the minus side in the Y-axis direction) toward the flat focusing portion 411. ing.

Further, the first current collector convex portion 523a has a second current collector convex portion 523b protruding in a direction intersecting the protruding direction (Y-axis direction) of the first current collector convex portion 523a. In the present embodiment, the second current collector convex portion 523b projects in a direction orthogonal to the projecting direction (Y-axis direction). Specifically, the second current collector convex portion 523b is formed so as to project from the tip of the first current collector convex portion 523a in all directions perpendicular to the projecting direction. That is, the second current collector convex portion 523b is a convex portion formed at the tip of the first current collector convex portion 523a in an annular shape so as to spread from the tip.

The protruding direction of the first current collector convex portion 523a and the second current collector convex portion 523b is not limited to the above direction, and may be a direction inclined from the above direction, and the protruding shape. Is not limited to the above. Further, the second current collector convex portion 523b may be formed not on the entire circumference of the tip of the first current collector convex portion 523a but only on a part of the entire circumference.

Further, in the joint portion 20, the flat focusing portion 411 of the electrode body 400 has a first electrode body convex portion 411a protruding toward the cover member 700. That is, the convex portion 411a of the first electrode body is a cylindrical convex portion protruding in a direction (plus side in the Y-axis direction) orthogonal to the joint surface (plane parallel to the XZ plane) between the flat focusing portion 411 and the cover member 700. Is. In other words, the convex portion 411a of the first electrode body is formed by the surface of the second portion 522a on the terminal side (the surface parallel to the XZ plane on the minus side in the Y-axis direction), the second portion 522a on the terminal side, and the flat focusing portion 411. It has a concave shape in the direction (plus side in the Y-axis direction) orthogonal to the joint surface (plane parallel to the XZ plane).

Further, the first electrode body convex portion 411a has a second electrode body convex portion 411b protruding in a direction intersecting the protruding direction (Y-axis direction) of the first electrode body convex portion 411a. In the present embodiment, the convex portion 411b of the second electrode body protrudes in a direction orthogonal to the protruding direction (Y-axis direction). Specifically, the second electrode body convex portion 411b is formed so as to project from the tip of the first electrode body convex portion 411a in all directions perpendicular to the protruding direction. That is, the second electrode body convex portion 411b is a convex portion formed at the tip of the first electrode body convex portion 411a in an annular shape so as to spread from the tip.

The protruding direction of the convex portion 411a of the first electrode body and the convex portion 411b of the second electrode body is not limited to the above direction, and may be a direction inclined from the above direction, and the protruding shape may also be used. Not limited to the above. Further, the second electrode body convex portion 411b may be formed not on the entire circumference of the tip of the first electrode body convex portion 411a but only on a part of the entire circumference.

Further, in the joint portion 20, the cover member 700 has a first cover convex portion 700a that protrudes in a direction away from the flat focusing portion 411. That is, the first cover convex portion 700a is a cylindrical convex portion protruding in a direction (plus side in the Y-axis direction) orthogonal to the joint surface (plane parallel to the XZ plane) between the flat focusing portion 411 and the cover member 700. is there. In other words, the convex portion 700a of the first cover is in a direction (Y-axis direction) orthogonal to the surface on the flat focusing portion 411 side from the surface on the flat focusing portion 411 side (the surface parallel to the XZ plane on the minus side in the Y-axis direction). It has a concave shape on the plus side).

Further, the first cover convex portion 700a has a second cover convex portion 700b protruding in a direction intersecting the protruding direction (Y-axis direction) of the first cover convex portion 700a. In the present embodiment, the convex portion 700b of the second cover projects in a direction orthogonal to the projecting direction (Y-axis direction). Specifically, the second cover convex portion 700b is formed so as to project from the tip of the first cover convex portion 700a in all directions perpendicular to the projecting direction. That is, the second cover convex portion 700b is a convex portion formed at the tip of the first cover convex portion 700a in an annular shape so as to extend from the tip.

The protruding direction of the first cover convex portion 700a and the second cover convex portion 700b is not limited to the above direction, and may be a direction inclined from the above direction, and the protruding shape is also described above. Is not limited. Further, the second cover convex portion 700b may be formed not on the entire circumference of the tip of the first cover convex portion 700a but only on a part of the entire circumference.

Next, a method of manufacturing the power storage element 10 will be described. 7A and 7B are flowcharts showing a method of manufacturing the power storage element 10 according to the embodiment of the present invention. Specifically, FIG. 7A is a flowchart showing a step of joining the current collector and the electrode body 400 in the manufacturing method of the power storage element 10. Further, FIG. 7B is a flowchart showing a process of forming the first convex portion and the second convex portion on the current collector. Since the positive electrode current collector 500 and the negative electrode current collector 600 have the same configuration, the positive electrode current collector 500 side will be described below, and the description of the negative electrode current collector 600 side will be omitted. ..

First, as shown in FIG. 7A, a thin portion having a thickness thinner than the other portions is formed in the electrode connecting portion 520 of the positive electrode current collector 500 (S102). Specifically, the second portion 522 (terminal side second portion 522a and tip side second portion 522b) shown in FIG. 4 is formed on the electrode connecting portion 520 by press working, cutting, or the like.

Then, the thin portion formed in the electrode connecting portion 520 and the electrode body 400 are joined by plastically deforming (S104). That is, the second portion 522 (terminal side second portion 522a and tip side second portion 522b) formed in the electrode connecting portion 520 and the flat focusing portion 411 of the positive electrode focusing portion 410 of the electrode body 400 are joined by caulking.

Here, in the case of joining by this plastic deformation (caulking) (S104 in FIG. 7A), as shown in FIG. 7B, first, a first convex portion is formed at the joining portion between the second portion 522 and the electrode body 400. (S202). That is, the first convex portion is formed on the second portion 522, the electrode body 400, and the cover member 700. Specifically, the terminal-side second portion 522a of the second portion 522, the flat focusing portion 411 of the electrode body 400, and the cover member 700 are stacked and arranged in this order, and the joining device ( Press the punch (convex part) of the tool) to deform it. More specifically, the joining tool is composed of a convex punch and a die. By arranging the die on the cover member 700 side and pressing the punch from the terminal side second portion 522a side, the terminal side first The second part 522a, the flat focusing part 411 and the cover member 700 are plastically deformed.

As a result, the first current collector convex portion 523a, the first electrode body convex portion 411a, and the first cover convex portion 700a are formed substantially at the same time. As shown in FIG. 6, the first current collector convex portion 523a, the first electrode body convex portion 411a, and the first cover convex portion 700a are formed of the terminal side second portion 522a, the flat focusing portion 411, and the cover member 700. The wall thickness is formed thinner than the other parts.

Returning to FIG. 7B, the second convex portion is then formed on the first convex portion (S204). That is, the first current collector convex portion 523a, the first electrode body convex portion 411a, and the first cover convex portion 700a have the second current collector convex portion 523b, the second electrode body convex portion 411b, and the second cover convex portion 700b. To form. Specifically, the tip portions of the first current collector convex portion 523a, the first electrode body convex portion 411a, and the first cover convex portion 700a are further pressed, and the second current collector convex portion 523b is applied to the tip portions. , The second electrode body convex portion 411b and the second cover convex portion 700b are formed.

In the present embodiment, the step of forming the first convex portion (S202) and the step of forming the second convex portion (S204) are performed substantially simultaneously by a series of presses, that is, by so-called clinch joining, the first convex portion is formed. The second convex portion is formed almost at the same time. The press may be performed twice so that the first convex portion is formed by the first press and the second convex portion is formed by the second press.

As described above, according to the power storage element 10 according to the embodiment of the present invention, the second portion 522 of the positive electrode current collector 500 is the first current collector convex that protrudes toward the electrode body 400 at the joint portion 20. It has a part 523a. That is, the second portion 522 of the positive electrode current collector 500 forms the convex portion 523a of the first current collector and bites into the electrode body 400, so that the positive electrode current collector 500 and the electrode body 400 are firmly joined. There is. Here, since the second part 522 is thinner than the first part 521, the first current collector convex portion 523a is formed with a small force to join the positive electrode current collector 500 and the electrode body 400. be able to. Therefore, since a small joining device can be used, it is possible to reduce the number of uncoated portions of the active material of the electrode body 400 and suppress a decrease in the energy density of the power storage element 10.

That is, for example, the joining device for joining the electrode connecting portion 520 of the positive electrode current collector 500 and the flat focusing portion 411 of the electrode body 400 is arranged so as to sandwich the electrode connecting portion 520 and the flat focusing portion 411 between the punch and the die. Will be done. Here, in the die, the thicker the member to be joined, the larger the inner diameter of the hole into which the punch is inserted needs to be increased. Therefore, a die having a small inner diameter can be used by joining the positive electrode current collector 500 at the thin second portion 522. If a die having a small inner diameter can be used, the width of the electrode connecting portion 520 (width in the X-axis direction) can be narrowed, so that the width (X) of the active material uncoated portion in the flat focusing portion 411 can be narrowed. Width in the axial direction) can be narrowed. As a result, the area of the active material uncoated portion of the electrode body 400 can be reduced, and the area of the active material layer of the electrode body 400 can be suppressed from being reduced, so that the energy density of the power storage element 10 is lowered. Can be suppressed.

As described above, according to the power storage element 10, the performance of the power storage element 10 is deteriorated while forming the first current collector convex portion 523a and firmly joining the electrode body 400 and the positive electrode current collector 500. It can be suppressed. Further, since the first part 521 of the positive electrode current collector 500 is thicker than the second part 522, the decrease in the strength of the positive electrode current collector 500 in the second part 522 is suppressed by the first part 521. Therefore, it is possible to suppress the deterioration of the performance of the power storage element 10.

Further, in the positive electrode current collector 500, at least a part of the first part 521 is arranged between the terminal connecting portion 510 connected to the positive electrode terminal 200 and the second portion 522 joined to the electrode body 400. .. That is, since a thick portion is arranged between the terminal connection portion 510 and the second portion 522, the strength between the terminal connection portion 510 and the second portion 522 can be secured, and the power storage element 10 can be used. It is possible to suppress the deterioration of the performance.

Further, in the positive electrode current collector 500, at least a part of the first part 521 is arranged between the second part 522 (between the terminal side second part 522a and the tip side second part 522b). That is, since the thick portion is arranged between the thin second portions 522, the strength between the second portions 522 can be secured, and the deterioration of the performance of the power storage element 10 can be suppressed. Can be done.

Further, the first convex portion (first current collector convex portion 523a, first electrode body convex portion 411a and first cover convex portion 700a) has a second convex portion (second current collector convex portion 523b, second electrode body). Since the convex portion 411b and the second cover convex portion 700b) are formed, the first convex portion is hard to come off. Therefore, it is possible to improve the bonding strength between the positive electrode current collector 500 and the electrode body 400.

Further, since the second convex portion is formed so as to project from the tip of the first convex portion in the entire circumferential direction, the bonding strength between the positive electrode current collector 500 and the electrode body 400 can be further improved. ..

Further, according to the method for manufacturing the power storage element 10 according to the embodiment of the present invention, a thin portion (second portion 522) thinner than the other portions is formed in the electrode connecting portion 520 of the positive electrode current collector 500. Then, the thin portion and the electrode body 400 are joined by plastic deformation (that is, by caulking). That is, by plastically deforming and joining the positive electrode current collector 500 and the electrode body 400 in the thin-walled portion, the positive electrode current collector 500 and the electrode body 400 can be joined with a small force. Therefore, since a small joining device can be used, the uncoated portion of the active material of the electrode body 400 can be reduced (the width of the uncoated portion of the active material is narrowed), and the performance of the power storage element 10 is suppressed from deteriorating. can do. Further, since the portion other than the thin portion of the positive electrode current collector 500 is thick, the power storage element is suppressed by suppressing the decrease in the strength of the positive electrode current collector 500 in the thin portion by the other portion. It is possible to suppress the deterioration of the performance of 10.

Since the negative electrode current collector 600 side has the same configuration as the positive electrode current collector 500 side, the same effect can be obtained.

(Modification example 1)
Next, a modification 1 of the above embodiment will be described. In the above embodiment, the cover member 700 is a flat plate-shaped member having a uniform thickness. However, in this modification, the cover member has a thin wall portion.

FIG. 8 is a cross-sectional view showing a configuration in which the positive electrode current collector 500 according to the first modification of the embodiment of the present invention is joined to the positive electrode focusing portion 410 of the electrode body 400. Specifically, the figure corresponds to FIG.

As shown in FIG. 8, the cover member 710 is arranged inside the flat focusing portion 411, and the terminal side second portion 522a and the tip side second portion 522b, the flat focusing portion 411, and the cover member 710 are mechanically connected to each other. Two joints 21 are formed by being joined (for example, joined by caulking). The cover member 710 is a cover that protects the flat focusing portion 411 arranged at a position sandwiching the flat focusing portion 411 of the positive electrode focusing portion 410 of the electrode body 400 with the electrode connecting portion 520. Similarly, the cover member 710 is arranged on the electrode connecting portion 530 side.

Here, the cover member 710 is a rectangular and flat plate-shaped member extending in the Z-axis direction along the flat focusing portion 411, and is a first cover portion 711 and a second cover thinner than the first cover portion 711. It has a part 712. Specifically, the cover member 710 has a plurality of second cover portions between the plurality of first cover portions 711 and the plurality of first cover portions 711, which are thinner than the plurality of first cover portions 711. It has 712 and. That is, the second cover portion 712 is a thin-walled portion formed on the cover member 710, and is formed to have a thickness of about 1/2 to 2/3 of that of the first cover portion 711 by, for example, press working or cutting. ing.

The second cover portion 712 is a portion joined to the positive electrode current collector 500 and the electrode body 400. Specifically, the second cover portion 712 is joined to the flat focusing portion 411 of the positive electrode focusing portion 410 at two locations, the terminal side second portion 522a and the tip side second portion 522b, to form the two joining portions 21. Has been done.

As described above, according to the power storage element according to the present modification, it is possible to suppress deterioration of the performance of the power storage element while firmly joining the electrode body 400 and the current collector as in the above embodiment. Can be done. In particular, according to this modification, since the cover member 710 is also joined to the electrode body 400 by the thin second cover portion 712, the positive electrode current collector 500 and the cover member 710 are joined to the electrode body 400 with a smaller force. Can be joined to. Therefore, since a smaller joining device can be used, it is possible to further suppress deterioration in the performance of the power storage element. Further, since the first cover portion 711 is thicker than the second cover portion 712, the first cover portion 711 suppresses the decrease in the strength of the cover member 710 in the second cover portion 712, thereby causing the power storage element. It is possible to suppress the deterioration of the performance.

In this modification, the configuration of the positive electrode current collector 500 on the electrode connection portion 520 side has been described in detail, but the same applies to the electrode connection portion 530 side, and further to the negative electrode current collector 600. .. The same applies to the following modified examples.

(Modification 2)
Next, a modification 2 of the above embodiment will be described. In the above embodiment, in the positive electrode current collector 500, at least a part (intermediate first part 521b) of the first part 521 is a plurality of second parts (terminal side second part 522a and tip side second part 522b). It was decided that it was placed between). However, in this modification, the first part 521 is not arranged between the plurality of second parts.

FIG. 9 is a cross-sectional view showing a configuration in which the positive electrode current collector 501 according to the second modification of the embodiment of the present invention is joined to the positive electrode focusing portion 410 of the electrode body 400. Specifically, the figure corresponds to FIG.

As shown in FIG. 9, the positive electrode current collector 501 in this modification replaces the intermediate first part 521b, the terminal side second part 522a, and the tip side second part 522b of the positive electrode current collector 500 in the above embodiment. It has a second part 522c. That is, the intermediate first part 521b in the above embodiment becomes a thin-walled part, and is integrated with the terminal side second part 522a and the tip side second part 522b to form the second part 522c in this modification. In other words, two joints 20 are formed in one second portion 522c.

As a result, the second part 522 has only one second part 522c, and the first part 521 has the terminal side first part 521a and the tip side first part 521c at positions sandwiching the second part 522. It becomes the configuration which has. Therefore, the first part 521 is not configured to be arranged between the plurality of second parts as in the above embodiment.

As described above, according to the power storage element according to the present modification, it is possible to suppress deterioration of the performance of the power storage element while firmly joining the electrode body 400 and the current collector as in the above embodiment. Can be done. In particular, according to this modification, since the second part 522 has only one second part 522c, the positive electrode current collector 501 can be easily manufactured.

In this modification, the configuration in which two joints 20 are formed in one second portion 522c is shown, but the configuration in which three or more joints 20 are formed in one second portion 522c. But it doesn't matter.

(Modification 3)
Next, a modification 3 of the above embodiment will be described. In the above embodiment, in the positive electrode current collector 500, at least a part (terminal side first part 521a) of the first part 521 is a terminal connection portion 510 and a second part (terminal side second part 522a). It was decided that it was placed between them. However, in this modification, the first part 521 is not arranged between the terminal connection part 510 and the second part.

FIG. 10 is a cross-sectional view showing a configuration in which the positive electrode current collector 502 according to the third modification of the embodiment of the present invention is joined to the positive electrode focusing portion 410 of the electrode body 400. Specifically, the figure corresponds to FIG.

As shown in FIG. 10, the positive electrode current collector 502 in this modification replaces the terminal side first part 521a and the terminal side second part 522a of the positive electrode current collector 500 in the above embodiment, and is replaced with the terminal side second part 522a. It has a part 522d. That is, the terminal-side first portion 521a in the above embodiment becomes a thin-walled portion and is integrated with the terminal-side second portion 522a to form the terminal-side second portion 522d in this modification.

As a result, the second part 522 has a terminal side second part 522d connected to the terminal connection part 510, and the first part 521 has an intermediate first part 521b and a tip side below the terminal side second part 522d. It has a configuration having the first part 521c. Therefore, the first part 521 is not configured to be arranged between the terminal connection part 510 and the second part 522 as in the above embodiment.

As described above, according to the power storage element according to the present modification, it is possible to suppress deterioration of the performance of the power storage element while firmly joining the electrode body 400 and the current collector as in the above embodiment. Can be done. In particular, since the position of the thin-walled portion formed on the current collector can be set in various ways as in the present modification, the degree of freedom in designing the current collector can be improved.

(Modification example 4)
Next, a modification 4 of the above embodiment will be described. In the above embodiment, in the positive electrode current collector 500, the first part 521 is arranged at a position sandwiching the second part 522 in the vertical direction. However, in this modification, the first part 521 is also arranged around the second part 522.

FIG. 11 is a perspective view showing the configuration of the positive electrode current collector 503 according to the fourth modification of the embodiment of the present invention. Note that the figure corresponds to FIG. 4, and shows the configuration of the positive electrode current collector 503 in a state before being joined to the electrode body 400.

As shown in FIG. 11, the positive electrode current collector 503 in the present modification is the terminal side second portion 522a and the tip side second portion 522b of the positive electrode current collector 500 in the above embodiment. It has a portion 522e and a front end side second portion 522f. Further, the positive electrode current collector 503 further has peripheral arrangement first portions 521d and 521e around the terminal side second portion 522e and the tip side second portion 522f. That is, the terminal-side second portion 522a and the tip-side second portion 522b in the above embodiment are oval-shaped recesses, and the peripheral arrangement first parts 521d and 521e in the present modification are formed around the recesses. ing.

As described above, in the positive electrode current collector 503, the electrode connecting portion 520 is formed with a second portion 522 (terminal side second portion 522e and tip side second portion 522f) which is an oval recess as a thin-walled portion. The configuration has a first part 521 (terminal side first part 521a, intermediate first part 521b, tip side first part 521c, peripheral arrangement first part 521d and 521e) around the second part 522. That is, at least a part of the first part 521 is arranged around the second part 522. The same applies to the electrode connection portion 530.

Then, as in the above embodiment, the joint portion 20 is formed in each of the terminal side second portion 522e and the tip side second portion 522f of the second portion 522. Although the terminal-side second portion 522e and the tip-side second portion 522f show elliptical recesses in the figure, they may be circular, elliptical, or rectangular recesses.

As described above, according to the power storage element according to the present modification, it is possible to suppress deterioration of the performance of the power storage element while firmly joining the electrode body 400 and the current collector as in the above embodiment. Can be done. In particular, according to this modification, since the thick portion is arranged around the thin second portion 522, the strength around the second portion 522 can be secured, and the performance of the power storage element can be improved. It can be suppressed from decreasing.

In this modification, the peripheral arrangement first part 521d and 521e are arranged so as to cover the entire circumference of the terminal side second part 522e and the tip side second part 522f, but they are arranged on a part of the entire circumference. It does not matter if the configuration is arranged only.

(Modification 5)
Next, a modification 5 of the above embodiment will be described. In the above embodiment, the second portion 522 of the positive electrode current collector 500 has a first convex portion protruding toward the electrode body 400 at the joint portion 20. However, in this modification, the electrode body 400 has a first convex portion that protrudes toward the second portion 522 at the joint portion.

FIG. 12 is a cross-sectional view showing the configuration of the joint portion 22 between the positive electrode current collector and the electrode body 400 according to the fifth modification of the embodiment of the present invention. Specifically, the figure corresponds to FIG.

As shown in FIG. 12, the second portion 522, the electrode body 400, and the cover member 700 of the positive electrode current collector project toward the second portion 522 side (plus side in the Y-axis direction in the figure) at the joint portion 22. It has a first convex portion. Further, the first convex portion has a second convex portion that protrudes in a direction intersecting the protruding direction of the first convex portion.

Specifically, the terminal-side second portion 522a of the second portion 522 has a first current collector convex portion 523d projecting toward the side opposite to the flat focusing portion 411 of the electrode body 400 at the joint portion 22. doing. Further, the flat focusing portion 411 of the electrode body 400 is a convex first electrode body that protrudes toward the terminal side second portion 522a of the second portion 522 (toward the side opposite to the cover member 700) at the joint portion 22. It has a part 411d. Further, the cover member 700 has a first cover convex portion 700d protruding toward the terminal side second portion 522a of the electrode body 400 at the joint portion 22.

Further, the first current collector convex portion 523d has a second current collector convex portion 523e protruding in a direction intersecting the projecting direction (Y-axis direction) of the first current collector convex portion 523d. Specifically, the second current collector convex portion 523e is formed so as to project from the tip of the first current collector convex portion 523d in all directions perpendicular to the projecting direction. Further, the first electrode body convex portion 411d has a second electrode body convex portion 411e protruding in a direction intersecting the protruding direction (Y-axis direction) of the first electrode body convex portion 411d. Specifically, the second electrode body convex portion 411e is formed so as to project from the tip of the first electrode body convex portion 411d in all directions perpendicular to the protruding direction. Further, the first cover convex portion 700d has a second cover convex portion 700e protruding in a direction intersecting the projecting direction (Y-axis direction) of the first cover convex portion 700d. Specifically, the second cover convex portion 700e is formed so as to project from the tip of the first cover convex portion 700d in all directions perpendicular to the projecting direction.

The protruding directions of the first convex portion and the second convex portion are not limited to the above-mentioned direction, and may be a direction inclined from the above-mentioned direction, and the protruding shape is not limited to the above-mentioned. Further, the second convex portion may be formed not on the entire circumference of the tip of the first convex portion but on only a part of the entire circumference.

As described above, the configuration in the present modification has a relationship in which the protruding direction of the first convex portion is opposite to that in the above-described embodiment at the joint portion. For example, when the second portion 522 of the positive electrode current collector abuts on the inside of the flat focusing portion 411 of the electrode body 400, the positional relationship between the second portion 522 and the cover member 700 is opposite to that of the above embodiment. become. In this case, since the cover member 700 is arranged on the outside, the joint portion 22 can be easily formed by denting the joint target portion from the cover member 700 side. Thereby, by applying this modification, the positive electrode current collector and the electrode body 400 can be easily joined.

Further, according to the power storage element according to the present modification, it is possible to suppress deterioration of the performance of the power storage element while firmly joining the electrode body 400 and the current collector as in the above embodiment. In particular, according to this modification, the electrode body 400 forms the first convex portion and the second convex portion and bites into the current collector, so that the current collector and the electrode body 400 are firmly joined. As a result, it is possible to prevent the performance of the power storage element from deteriorating while firmly joining the electrode body 400 and the current collector.

In this modified example, the cover member 700 is a flat plate-shaped member having a uniform thickness in the state before joining, but a thin-walled portion is formed at a position corresponding to the joined portion 22 as in the above-mentioned modified example 1. You may be.

Although the power storage element according to the embodiment of the present invention and the modified example thereof has been described above, the present invention is not limited to the embodiment and the modified example thereof. That is, it should be considered that the embodiments disclosed this time and examples thereof are examples in all respects and are not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended that all modifications within the meaning and scope equivalent to the scope of claims are included.

For example, in the above embodiment and its modified example (excluding the modified example 2), it is assumed that one joint portion is formed for one second portion in the current collector. However, the number of joints is not limited, and a plurality of joints may be formed for one second part. In this case, the current collector and the electrode body 400 can be joined more firmly.

Further, in the above-described embodiment and its modification, it is determined that the second convex portion is formed on the first convex portion of the current collector, the electrode body 400, and the cover member. However, a configuration in which the second convex portion is not formed on at least one first convex portion of the current collector, the electrode body 400, and the cover member may be used. In particular, in the configuration in which the second convex portion is not formed on the first convex portion of the cover member, after joining the electrode body 400 and the cover member, the joined electrode body 400 and the cover member can be easily removed from the die of the joining device. be able to. In this case, in order to make it easier to remove from the die, the inclination angle of the side surface of the first convex portion of the cover member (the angle formed by the side surface of the first convex portion and the surface at the base, that is, for example, in FIG. 6, the first cover The angle formed by the surfaces of the convex portion 700a on both sides in the Z-axis direction and the surfaces of the cover member 700 on the plus side in the Y-axis direction) may be obtuse. In other words, the outer diameter of the first convex portion of the cover member (that is, the diameter of the cross section when the first cover convex portion 700a is cut in the XZ plane in FIG. 6) is the tip (the end on the plus side in the Y-axis direction). It does not matter if the configuration becomes smaller toward.

Further, in the above-described embodiment and its modification, the positive electrode current collector has the electrode connecting portion 520 having a tip-side first portion 521c thicker than the second portion 522. However, the tip side first part 521c may be formed to be equal to or thinner than the second part 522 or thinner than the second part 522, and the positive electrode current collector has the tip side first part 521c. It does not matter if there is no configuration. However, since the tip side first part 521c can be utilized, such as the warpage of the electrode connecting portion 520 can be reduced by holding the tip side first part 521c during the manufacture of the positive electrode current collector, the positive electrode side first part 521c can be utilized. The current collector preferably has a tip-side first portion 521c. The same applies to the electrode connecting portion 530 and the negative electrode current collector 600.

Further, in the above-described embodiment and its modification, the positive electrode current collector is joined to the positive electrode focusing portion 410 of the electrode body 400. However, the electrode body 400 has a conductive member such as a lead connected to the positive electrode focusing portion 410, and the positive electrode current collector may be joined to the conductive member. In this case, the joint portion 20 is a joint portion between the second portion 522 of the electrode connection portion 520 of the positive electrode current collector and the conductive member, and one of the second portion and the conductive member is the other in the joint portion. It has a configuration having a first convex portion protruding toward. The same applies to the negative electrode current collector 600.

Further, in the above-described embodiment and its modification, the current collector, the electrode body 400, and the cover member are joined, but members other than these may also be joined together.

Further, in the above-described embodiment and its modification, the current collector and the electrode body 400 are joined only at the joint portion, but in addition to the joint at the joint portion, the joint by another joining method can be used. It may be done. Other bonding methods include, for example, ultrasonic welding, resistance welding, arc welding, and welding by irradiating a laser or electron beam.

Further, in the above-described embodiment and its modification, the power storage element is provided with a cover member at the joint between the current collector and the electrode body 400, but the cover member may not be provided. However, from the viewpoint of strength and the like, the power storage element preferably includes the cover member.

Further, in the above-described embodiment and its modification, for example, as shown in FIG. 6, the positive electrode current collector, the electrode body 400, and the cover member are formed so as to project to the plus side in the Y-axis direction at the joint portion 20. And said. However, the surface of the cover member on the positive side in the Y-axis direction may be formed flat by press working or the like while maintaining the state in which the first convex portion is formed on the second portion 522 and the electrode body 400.

Further, in the above-described embodiment and its modification, in the positive electrode current collector, the joint portions 20 are formed in all the second portions 522 of the electrode connecting portions 520, but some of the second portions 522 are formed. The joint portion 20 may not be formed in the joint portion 20. Further, in the positive electrode current collector, it is assumed that the joint portions are formed on both of the electrode connection portions 520 and 530, but the joint portions are formed on only one of the electrode connection portions 520 and 530. It may be. Further, in the power storage element, it was decided that a junction was formed on both the positive electrode current collector and the negative electrode current collector, but the junction was formed on only one of the positive electrode current collector and the negative electrode current collector. The configuration may be set.

Further, in the above-described embodiment and its modification, clinch bonding is exemplified as an example of plastically deforming the current collector and the electrode body 400 when the current collector and the electrode body 400 are bonded. However, the present invention is not limited to this, and a bonding by caulking different from the clinch bonding (such as a form in which only the first convex portion is formed by pressing) may be used, or a bonding using rivets may be used.

Further, in the above-described embodiment and its modification, the electrode body 400 is a so-called vertical winding type electrode body in which the winding shaft is parallel to the lid body 110. However, the electrode body 400 may be a so-called horizontal winding type electrode body in which the winding axis is perpendicular to the lid body 110. In this case, the tab of the electrode body and the thin portion of the current collector are joined, and at the joint portion, one of the thin portion and the tab of the electrode body has a first convex portion protruding toward the other. It becomes.

Further, a form constructed by arbitrarily combining the components included in the above-described embodiment and its modifications is also included in the scope of the present invention. For example, the configuration of the modified example 1 may be applied to the modified examples 2 to 5, the configuration of the modified example 2 may be applied to the modified examples 3 to 5, and the configuration of the modified example 3 may be applied to the modified examples 4 and 4. 5 may be applied, or the configuration of the modified example 4 may be applied to the modified example 5.

Further, the present invention can be realized not only as such a power storage element but also as a current collector (positive electrode current collector or negative electrode current collector) included in the power storage element.

The present invention can be applied to a power storage element or the like capable of suppressing deterioration of the performance of the power storage element while firmly joining the electrode body and the current collector.

10 Power storage element 20, 21, 22, 30 Joint part 100 Container 110 Lid 110a, 110b Through hole 111 Container body 200 Positive electrode terminal 210, 310 Protruding part 300 Negative electrode terminal 400 Electrode body 410 Positive electrode focusing part 411, 412 Flat focusing part 411a 411d 1st electrode body convex part 411b, 411e 2nd electrode body convex part 420 Negative electrode focusing part 500, 501, 502, 503 Positive electrode current collector 510 Terminal connection part 511, 611 Opening part 520, 530 Electrode connection part 521 First Part 521a Terminal side first part 521b Intermediate first part 521c Tip side first part 521d, 521e Peripheral arrangement first part 522, 522c Second part 522a, 522d, 522e Terminal side second part 522b, 522f Tip side second part 523a, 523d 1st current collector convex part 523b, 523e 2nd current collector convex part 600 Negative electrode current collector 700, 710 Cover member 700a, 700d 1st cover convex part 700b, 700e 2nd cover convex part 711 1st cover Part 712 Second cover part

Claims (3)

A power storage element including an electrode body and a current collector.
The electrode body has a focusing portion in which electrode plates are laminated.
The current collector has an electrode connecting portion connected to the focusing portion, and has an electrode connecting portion.
The electrode connecting portion has a first portion and a second portion which is thinner than the first portion and is joined to the focusing portion.
One of the second portion and the focusing portion is a power storage element having a first convex portion protruding toward the other at the joint portion. further,
A cover member is provided at a position sandwiching the electrode body with the electrode connecting portion.
The power storage element according to claim 1, wherein the cover member has a first cover portion and a second cover portion that is thinner than the first cover portion and is joined to the electrode body. .. A method for manufacturing a power storage element including an electrode body having a focusing portion on which electrode plates are laminated and a current collector having an electrode connecting portion connected to the focusing portion.
A first part and a second part thinner than the first part are formed in the electrode connecting portion.
A power storage element that joins the second portion and the focusing portion by plastically deforming, and forms a first convex portion that protrudes toward the other at the joint portion at either the second portion or the focusing portion. Manufacturing method.

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